A powder coating material has a feature that it is solvent free, and its application range has been expanded in recent years, as consciousness for environmental protection has increased. Especially, a fluororesin powder coating material is capable of meeting a demand for maintenance-free by virtue of the weather resistance performance which the fluororesin specifically has, and its applications are expected to increase.
Of a coating film comprising a fluororesin powder coating material, one feature is a high surface hardness. On the other hand, the impact strength of the coating film is poor as compared with a powder coating material comprising a polyester.
It has been known to add particles having a so-called core/shell structure to a powder coating material comprising e.g. a polyester in order to improve impact resistance. However, if such conventionally known particles having a core/shell structure are added to a powder coating material containing a fluororesin as the main component, since the weather resistance performance of the particles is inferior to the weather resistance performance of the fluororesin, weather resistance performance of the coating film tends to deteriorate resultingly. Further, the gloss tends to be low since the refractive indices of the fluororesin and the particles are significantly different, and characteristics of the powder coating material containing a fluororesin as the main component can not adequately be exhibited. Further, since dispersibility of the particles into the fluororesin is inadequate, the effect of improving the impact resistance tends to be inadequate.
The present invention has been made to overcome the above drawbacks, and it is an object of the present invention to provide a composition which can improve impact resistance of a coating film while maintaining superior weather resistance of a fluororesin powder coating material and gloss of the coating film.